Early osseointegration driven by the surface chemistry and wettability of dental implants

Objective The objective of this study was to investigate the impact of two different commercially available dental implants on osseointegration. The surfaces were sandblasting and acid etching (Group 1) and sandblasting and acid etching, then maintained in an isotonic solution of 0.9% sodium chloride (Group 2). Material and Methods X-ray photoelectron spectroscopy (XPS) was employed for surface chemistry analysis. Surface morphology and topography was investigated by scanning electron microscopy (SEM) and confocal microscopy (CM), respectively. Contact angle analysis (CAA) was employed for wetting evaluation. Bone-implant-contact (BIC) and bone area fraction occupied (BAFO) analysis were performed on thin sections (30 μm) 14 and 28 days after the installation of 10 implants from each group (n=20) in rabbits' tibias. Statistical analysis was performed by ANOVA at the 95% level of significance considering implantation time and implant surface as independent variables. Results Group 2 showed 3-fold less carbon on the surface and a markedly enhanced hydrophilicity compared to Group 1 but a similar surface roughness (p>;0.05). BIC and BAFO levels in Group 2 at 14 days were similar to those in Group 1 at 28 days. After 28 days of installation, BIC and BAFO measurements of Group 2 were approximately 1.5-fold greater than in Group 1 (

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

Objective: This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Methods: Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results: The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>;0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. Conclusion: The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA,

Comparing the Long-Term Success Rates of Tooth Preservation and Dental Implants: A Critical Review

Implant therapy is considered a predictable, safe, and reliable rehabilitation method for edentulous patients in most clinical scenarios. Thus, there is a growing trend in the indications for implants, which seems attributable not only to their clinical success but also to arguments such as a more “simplified approach” based on convenience or the belief that dental implants are as good as natural teeth. Therefore, the objective of this critical literature review of observational studies was to discuss the evidence concerning the long-term survival rates and treatment outcomes, comparing endodontically or periodontally treated teeth with dental implants. Altogether, the evidence suggests that the decision between keeping a tooth or replacing it with an implant should carefully consider the condition of the tooth (e.g., amount of remaining tooth and degree of attachment loss and mobility), systemic disorders, and patient preference. Although observational studies revealed high success rates and long-term survival of dental implants, failures and complications are common. For this reason, attempts should be made to first save maintainable teeth over the long-term, instead of immediately replacing teeth with dental implants

Impact of synthesis temperature on biosorption and biocompatibility of nanostructured carbonated hydroyapatites

A hidroxiapatita (HA) é um dos materiais mais utilizados internacionalmente em aplicações médicas envolvendo a substituição/regeneração óssea e dentária e, mais recentemente, em terapias celulares, devido às suas propriedades de biocompatibilidade e bioatividade. Contudo, sua utilização pelo Sistema Único de Saúde foi descontinuada em função de sua baixa bioabsorção. A hidroxiapatita carbonatada (cHA) foi desenvolvida com o objetivo de melhorar as propriedades de dissolução da HA em fluidos corporais e ampliar sua capacidade terapêutica pela modificação de sua composição química. O objetivo deste trabalho foi avaliar a biocompatibilidade e bioabsorção das cHAs sintetizadas a 5°C, 37°C e 90°C, não sinterizadas, comparadas à HA estequiométrica sintetizada a 90°C e sinterizada. Os materiais foram caracterizados utilizando a Difração de Raio X (DRX), a Espectroscopia Vibracional no Infra Vermelho por Transformada de Fourier (EVIVTF) e Microscopia Eletrônica de Varredura (MEV). A citotoxicidade dos diferentes biomateriais foi mensurada através da atividade mitocondrial (redução do XTT) e integridade da membrana celular (incorporação de Vermelho Neutro) utilizando préosteoblastos murinos MC3T3-E1 tratados com meio condicionado pelos diferentes biomateriais. Camundongos Balb/C (n=75) foram distribuídos aleatoriamente em 5 grupos experimentais. Após a anestesia, tricotomia e antissepsia, realizou-se uma incisão de 10 mm no dorso dos camundongos para implantação subcutânea de esferas dos biomateriais processados nas temperaturas de 5ºC (Grupo 1), 37ºC (Grupo 2), 90°C (Grupo 3), HA 90°C/sinterizada (Grupo 4) e nenhuma implantação (Grupo 5, sham) seguido de sutura. Nos períodos experimentais de 1, 3 e 9 semanas, os animais foram submetidos a eutanásia, as amostras foram coletadas e processadas para inclusão em parafina e coradas com hematoxilina e eosina para avaliação descritiva e semiquantitativa do efeito biológico dos biomateriais no tecido subcutâneo segundo a norma ISO 10993-6:2007. Mastócitos foram identificados por coloração com azul de toluidina e quantificados. Os difratogramas das cHAs evidenciaram picos correspondentes ao de uma HA padrão, mas notou-se alargamento da base dos picos, sugerindo aumento do grau de dissolução dos biomateriais. As análises em EVIVTF confirmaram a presença de carbonato e água nas cHAs testadas. As micrografias eletrônicas de varredura exibiram diferentes morfologias das cHAs possivelmente relacionadas ao método de gotejamento durante a síntese além de diferenças na superfície quando comparadas com a HA estequiométrica. Todos os materiais avaliados foram atóxicos nos ensaios in vitro. In vivo, a macroscopia do tecido reacional dos grupos das cHAs apresentaram sinais de maior bioabsorção; a análise histológica do efeito biológico local após implantação demonstra que as cHAs e HA foram, respectivamente, levemente e moderadamente irritantes. A densidade de mastócitos para a HA 90°C aumentou significativamente em relação ao grupo sham e no grupo cHA 37°C, houve diminuição tempo dependente da densidade de mastócitos (p<0,05). Foi possível concluir que as cHAs estudadas mostraram-se biocompatívies e bioabsorvíveis, principalmente as sintetizadas em 5°C e 37°C, apontando esses materiais como potenciais substitutos à HA estequiométrica em aplicações biomédicas regenerativasHydroxyapatite (HA) is one of the most common materials used internationally in medical applications involving bone and dental substitution/regeneration and, more recently, in cellular therapies, due to its biocompatibility and bioactivity properties. However, due to the low bioabsorption of HA, its use by the Unified Health System of Brazil was discontinued. Carbonated HA (cHA) was developed with the objective of improving the dissolution properties of HA in body fluids and broadening the therapeutic capacity of HA by modifying its chemical composition. The objective of this study was to evaluate the biocompatibility and bioabsorption of unsintered cHA microspheres (cHAs) synthesized at 5°C, 37°C and 90°C compared to sintered stoichiometric HA synthesized at 90°C. The materials were characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) methods. The cytotoxicity of the different biomaterials (BMs) was measured via the mitochondrial activity [the reduction of 2, 3-bis (2- methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT)] and cellular membrane integrity (the incorporation of neutral red) of MC3T3- E1 murine pre-osteoblasts treated with media conditioned with the different BMs. Balb/C mice (n=75) were randomly distributed into 5 experimental groups. After anesthesia, trichotomy and antisepsis, a 10-mm incision was made in the dorsum of the mice to subcutaneously implant the BM microspheres processed at 5°C (Group 1), 37°C (Group 2) and 90°C (Group 3), the sintered HA processed at 90°C (Group 4, control) or no implantation (Group 5, sham); the incision was then sutured. After 1, 3 and 9 weeks, the animals were euthanized. Samples were collected and processed for inclusion in paraffin and stained with hematoxylin and eosin for evaluation of the biological effect of the BMs on the subcutaneous tissue according to the ISO 10993-6:2007 standard. Mast cells were identified by staining with toluidine blue and quantified. Diffractograms of the cHAs displayed peaks corresponding to an HA standard, but a broadening of the base of the peaks was noted, suggesting an increase in the degree of dissolution of the BMs. The FTIR analyses confirmed the presence of carbonate and water in the tested cHAs. The scanning electron micrographs revealed different morphologies of the cHAs, possibly related to the dripping synthesis method in addition to surface differences compared to stoichiometric HA. All of the evaluated materials were non-toxic in the in vitro tests. In vivo, the macroscopic tissue reactions of the groups implanted with cHAs revealed signs of increased bioabsorption; the histological analysis of the local biological effects after implantation demonstrates that the cHAs and HA were slightly and moderately irritating, respectively. The density of mast cells for the HA 90°C group increased significantly in relation to the sham group, and in the cHA 37°C group, there was a decrease in time depending on the density of mast cells (p<0.05). It is possible to conclude that the studied cHAs are biocompatible and bioabsorbable, primarily those synthesized at 5°C and 37°C, indicating that these materials are potential substitutes for stoichiometric HA in regenerative biomedical applications70 f

The role of ASC protein in bone metabolism associated with the use of different biomaterials

Uma das estratégias principais na medicina regenerativa é o preenchimento de defeitos ósseos com materiais biocompatíveis, a fim de otimizar o reparo ósseo funcional. Em particular, as propriedades como osteocondução e bioabsorção são melhoradas pela substituição parcial de CO 3-2 e PO 3-2 na hidroxiapatita (HA), um dos materiais mais utilizados mundialmente nas aplicações médicas. No entanto, a implantação de biomateriais pode apresentar reações inflamatórias nos estágios iniciais. Estudos recentes identificaram o papel da proteína ASC como mediador da resposta inflamatória devido ao recrutamento e formação do complexo inflamassoma. Os camundongos nocauteados para a proteína ASC (KO) apresentam resistência a doenças inflamatórias, como a artrite reumatóide e a esclerose múltipla, mas as contribuições da proteína ASC no reparo ósseo e na resposta biológica durante a implantação de biomateriais inorgânicos ainda não foram investigadas. Objetivou-se investigar a função de ASC na deposição de osso de novo avaliando a expressão genética do mRNA dos diferentes genes envolvidos na inflamação e reparo ósseo em resposta a HA, HA contendo carbonato (CHA) ou estrôncio e carbonato (SrCHA). Em seguida, células osteoprogenitoras primárias de camundongos do tipo selvagem/C57BL/6 e ASC KO foram coletadas e expostas aos meios condicionados pelos biomateriais. Através de análise histoquímica a coloração positiva para osteoblastos, fosfatase alcalina (ALP) e para osteoclastos, fosfatase ácida resistente ao tartarato (TRAcP) foram detectadas. Posteriormente, para validar a hipótese de que a ASC regula a diferenciação de osteoblastos e a deposição de osso de novo, camundongos de ambos os genótipos foram submetidos a implantação de HA, CHA e SrCHA na região de subcutâneo e tíbia. A análise semiquatitativa da resposta inflamatória foi avaliada segundo a Norma ISO 10993:6:2016. O processo de reparo ósseo em tíbia foi avaliado através de análises histológica, histomorfométrica e imuno-histoquímica. A microtomografia computadorizada (µCT) foi utilizada para confirmar os dados. Testes de Elisa para identificação de RANKL e BALP circulantes foram realizados. A cultura primária de osteoblastos do grupo ASC KO apresentou níveis menores de ALP quando comparada com as células do tipo selvagem, independente da exposição indireta aos diferentes biomateriais, sugerindo ASC como uma nova proteína envolvida na diferenciação dos osteoblastos in vitro. Os resultados in vivo mostraram que os camundongos ASC KO não foram capazes de curar completamente os defeitos em tíbia aos 28 dias, independente do biomaterial utilizado, enquanto os defeitos da tíbia de tipo selvagem apresentavaram maior volume de osso novo na análise histomorfométrica (p=0.03), confirmado pela marcação de RUNX2. Em conjunto, nossos resultados sugerem fortemente que a deposição de osso de novo é um evento biológico ASC-dependente, que deve ser explorado no campo da bioengenharia óssea.One of the principal strategies in regenerative medicine is to fill bone defects with biocompatible materials in order to support functional bone healing. In particular, properties such as osteoconductivity and bio-absorption are improved by partial substitution of CO 3-2 and PO 3-2 in hydroxyapatite (HA), one of the most common materials used globally in medical applications. However, the implantation of biomaterials may present clinical limitations such as inflammatory reactions at the early stages. Recent studies demonstrate the roile of ASC protein as a mediator of the inflammatory response due to the recruitment and formation of the inflammasome complex. Mice knocked out for protein (ASC KO) present resistance to inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis, but the contributions of the ASC protein in the bone repair and biological response to inorganic biomaterials for implanting have not been yet investigated. The objective was to investigate the role of ASC in the bone de novo deposition evaluating the mRNA gene expression of the different genes involved in inflammation and bone healing in response to HA, HA containing carbonate (CHA) or strontium and carbonate (SrCHA). Next, primary osteoprogenitor cells from wild type/C57BL/6 and ASC KO mice both genotypes were collected end exposed to conditioned medium of different biomaterials (HA, CHA and SrCHA). Through histochemical analysis the positive staining for osteoblasts, alkaline phosphatase (ALP) and for osteoclasts, tartrate resistant acid phosphatase (TRAcP) were detected. Subsequently, to validate the hypothesis that ASC protein regulates osteoblast differentiation and the bone de novo deposition, mice from both genotypes were submitted to the implantation of HA, CHA and SrCHA in the subcutaneous and tibia region. The semiquatitative analysis of the inflammatory reaction was evaluated according to ISO 10993: 6: 2016. The healing process of tibia defects was evaluated through histological, histomorphometric and immunohistochemical analysis. Computerized microtomography (µCT) was used to confirm the data. Elisa tests for identification of circulating RANKL and BALP were performed. The primary culture of osteoblasts from the ASC KO group showed lower levels of ALP when compared to wild type cells, independent of indirect exposure to different biomaterials, suggesting ASC as a novel protein involved in the differentiation of osteoblasts in vitro. The set of in vivo results showed that the ASC KO mice were not able to complete the healing of tibia defects at 28 days, regardless of the biomaterial used, whereas the defects in tibia of wild type group presented a larger volume of new bone formation in histomorphometric analysis (p=0.03) that was confirmed by RUNX2. Overall, our results strongly suggest that de novo bone deposition is an ASC-dependent biological event, which should be explored in the field of bone bioengineering.89f

PERCEPÇÃO DA POPULAÇÃO IDOSA RELATIVO AO USO E DESCARTE CORRETO DE MEDICAMENTOS

Objetivos: A pesquisa tem por objetivo conhecer os hábitos dos idosos em relação ao uso e descarte dos medicamentos visando ao mesmo tempo orientar acerca dos riscos quando os medicamentos são incorretamente administrados/conservados. Método: Em continuação às atividades desenvolvidas nos anos anteriores, realiza-se pesquisa-ação domiciliar e palestras explicativas nas Unidades Básicas de Saúde, objetivando conscientizar a população idosa do município de Passo Fundo – RS, promovendo ações adequadas sobre o tema. Resultados: Osdados demonstram que a população idosa utiliza mais com maior frequência medicamentos para o sistema cardiovascular(uso contínuo) e para o sistema músculo-esquelético (farmácia caseira). Quanto às condições de identificação/embalagem e descarte, os resultados foram satisfatórios, porém, não o armazenamento. Conclusão: Percebe-se a necessidade e a importância da educação continuada para indivíduos dessa faixa etária, relativo ao uso, armazenamento,cuidados e descarte de medicamentos